Simrad SD570, Руководство оператора

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Simrad SD570
22 850--160139 / A
5.2 Pulse form
With this function one may choose the form of the transmitter
pulse:
PULSE FORM.:
CW SHORT
CW NORMAL
CW LONG
*FM AUTO
FM 1
FM 2
FM 4
FM 8
CW (Continuous wave):
The frequency of the transmitter pulse is here constant. There is
a choice between three pulse lengths: short, normal and long. In
addition, the length of the pulse will change automatically in
accordance with chosen range. The table below shows the
different pulse lengths for CW and FM. The pulse length is given
in milliseconds (ms).
RANGE
(meters)
CW -- PULSE LENGTH (ms) FM
AUTO (meters)
SHORT NORMAL LONG
AUTO
125 0.6 1.25 3.75 FM4
250 1.25 2.5 7.5 FM4
375 2 3.75 11.25 FM4
500 2.5 5 15 FM4
750 3.75 7.5 22.5 FM4
1000 5 10 30 FM8
1500 7.5 15 45 FM8
2000 10 20 50 FM8
3000 15 30 50 FM8
4000 20 40 50 FM8
FM (Frequency modulation):
In the FM mode the transmitter pulse is frequency modulated.
This provides a stable echo presentation and greater ability of
detection as noise and reverberation are reduced.